1. Field of the Invention
The present invention relates to a vehicle illumination lamp employing a light-emitting element, such as a light-emitting diode, as a light source.
2. Description of Related Art
In recent years, an illumination lamp employing a light-emitting element, such as a light-emitting diode, as a light source has been developed as a vehicle illumination lamp, such as a headlamp.
In relation to the above, Japanese Patent-Publication 2004-95480 discloses a vehicle illumination lamp in which a projection lens is disposed on an optical axis extending in a longitudinal direction of the lamp, and in which a light-emitting element is disposed to the rear of the projection lens.
In the vehicle illumination lamp disclosed in JP 2004-95480, the light-emitting element is disposed adjacent to the rear of a near focal point of the projection lens on the optical axis. A shade for shielding light originating from the light-emitting element is disposed adjacent before the light-emitting element in such a manner that an upper edge of the shade passes through the rear focal point of the projection lens. In addition, the vehicle illumination lamp is configured such that light originating from the light-emitting element is illuminated forward through the projection lens, to thus form a light distribution pattern as a reversed projection image of an image of the light source which is formed on a rear focal plane of the projection lens; and, in conjunction therewith, to form a cutoff line as a reversed projection image of the upper edge of the shade.
However, the light-emitting element of the vehicle illumination lamp disclosed in JP 2004-95480 is configured such that the light-emitting chip is sealed by a substantially hemispherical sealing resin member. Accordingly, the image of the light source formed from light-originating from the light-emitting element on the rear focal plane of the projection lens is enlarged by means of a convex lens. Hence, there arises a problem that a light distribution pattern having a sharp cutoff line cannot be formed.
The present invention has been conceived in view of the above circumstances, and aims at providing a vehicle illumination lamp, which employs a light-emitting element as a light source, being capable of forming a light distribution pattern having a sharp cutoff line.